diff --git a/registry.txt b/registry.txt
index ef763dfa..8453f671 100644
--- a/registry.txt
+++ b/registry.txt
@@ -5599,3 +5599,4 @@ https://github.com/107-systems/107-Arduino-CriticalSection.git|Contributed|107-A
 https://github.com/uldara1/Modbus.git|Contributed|Modbus
 https://github.com/SyntaxHarvy/HaCEspSockets.git|Contributed|HaCEspSockets
 https://github.com/nkaaf/Arduino-Regression.git|Contributed|Regression
+https://github.com/RobTillaart/MHZCO2.git|Contributed|MHZCO2